Review of methods to measure internal contamination in an emergency

Abstract

In the event of a radiation emergency, people close to the site of the incident may be exposed to radiation by external exposure, or as a result of intakes of radioactive material. For these incidents it may be necessary to monitor members of the public both for external and internal contamination. This work reviews currently available equipment for the assessment of internal exposure following an emergency. It concentrates on incidents involving the spread of radioactive material and on contamination by radionuclides which emit penetrating radiation. It is essential that this monitoring is carried out as soon as possible so that people who have been exposed at a level which could have an effect on health can be identified and receive prompt medical assessment. Proposed action levels to identify people who need medical attention are reviewed to determine the required sensitivity of monitoring equipment. For releases containing gamma-ray emitting radionuclides the best means of measuring internal contamination is to use detectors placed close to the body (whole body or partial body monitoring). Laboratory based whole body monitors could be used but these may well be inconveniently located and so equipment which can be deployed to the site of an incident has been developed and these are described. The need for rapid selection and prioritisation of people for monitoring, methods to deal with potentially high numbers of contaminated people and the requirement for a means of rapidly interpreting monitoring information are also discussed.It has been found that for many types of incidents and scenarios, systems based on unshielded high-resolution detectors and hand-held instruments do have the required sensitivity to identify people who require medical assessment.

Treatment of radiological contamination: a review

“…Direct methods consist of the measurement, with external detectors, of the radiation emitted by the radionuclides deposited inside the body (18). They can only be used for radionuclides emitting penetrating radiation, i.e.…”

“…Therefore, it is essential to know which radioactive contaminants are involved, their chemical behavior, and biodistribution. Internal contamination should be treated in several ways, depending on the route of entry and chemical properties of the material (5,18). Urine analysis for radioactive contaminant provides a useful assessment of the existing systemic burden.…”

“…Urine analysis for radioactive contaminant provides a useful assessment of the existing systemic burden. Urine analysis can be particularly useful when equipment and facilities for external detection of radionuclides are not available on a routine basis (18,19). Except when 24-hour samples are collected, some correction of the concentration measurement may be required to account for abnormal conditions of high or low fluid intake or excessive loss of water by perspiration.…”

“…Another possible means of estimating the internal contamination in an individual is to measure the radionuclide content of a blood sample. Blood samples show less fluctuation in radionuclide content than do urine samples, but the sensitivity of the analysis is limited, due to the amount of blood that can be withdrawn from an individual, particularly in the event of an accident with severe injury (17,18).…”

Preparing for a “dirty bomb” attack: the optimum mix of medical countermeasure resources

“…The triage of patients is not possible by simple clinical examination, but only by whole-body measurement of radioactivity after superficial decontamination. The measurement of radioactivity is possible with mobile equipment, but the requirements on the devices and detection limits depend on the radionuclide(s) because of different types and energies of the emitted radiation [28]. Monitoring portals permit a high measurement throughput with a limited detection limit.…”